Electric circuit control



March 28,l 1933. 4 A. Ross l ELECTRIC CIRCUIT CONTROL Filed March 24.1930 U'U LIU LIULJ :EF l.

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R'fHUR IRQSS INVENTOR ATTORNEY l Patented Mar. 28, 1933 UNITED STATESPATENT OFFICE ARTHUR`ROSS, F LYNBROOK, NEW YORK, ASSIGNOR T0 WARNERBROS. PICTURES,

' INC., OF NEW YORK, N. Y., A CORPORATION 0F DELAWARE i ELECTRIC CIRCUITCNTROL Application led Harch 24, 1930. Serial No. 438,491.

This invention relates to contacting mechanisms for 1am circuitsparticularly to those of the type uti ized in controlling the lampcircuits of a continuous and step film print- 5 ing machine. l j

In lm printing machines an elecrical contacting mechanism is utilizedfor varying the resistance of electric lamp circuits in accordance witha predetermined time relationship. Certain mechanisms ofthis typecomprise a bank of contacting bars having spaced holes for the receptionof contact plugs which plugs may be arranged in any desired pattern onthe bank. Contact has been made with these plugs, in accordance with theprior art, by a series of s ring pressed buttons positioned in a bar obrass material, which is moved parallel to the face of the contact bankby gravity under control of suitable catch mechanisms, the springpressed buttons in the bar engaging with the contact plugs as the barmoves downwardly. Troule hasbeen experienced in creating a perfectcontact between the plugs and buttons and it has always been founddiflicult to keep the friction between the plugs and buttons suficientlylow to permit the bar to fall freely and smoothly without interruption.

It is an object of my invention to provide an improved form of contactmeans for contacting with the plugs of a contact bank whereby smooth andvery free action will always be obtained, while at the same time makingan eiiicient closure of the circuit between the contacts.

In accordance with my invention I obtain the above mentioned objects andadvantages by providing a contacting mechanism comprising a plvotallymounted arm carrying at its free end a cam-like contact surface. Thisarm is mounted on an insulating member with its longitudinal axissubstantially arallel to the plane of the contact bank and eld in thisposition by a small spring, which serves to press the arm forwardlyagainst a stop, this stop being so related that the camlike end of thearm engages the plugs with a wiping contact upon movement of theinsulating element holding it. This cam con- 50 tact rotates the armagainst the action of the spring, whereby cfree movement of the arm1past the lug is permitted. By making t e arm re atively long and byproperly shaping its cam face to a entle rise, a very smooth action isobtained t at is always uniform and which therefore insures efficientoperation of the associated electric circuit.

My invention will be more clearly explained in the following descriptionand the accompan ing drawing.

vIn the rawing, Fig. 1 shows in elevation and partly in section acontacting mechanism embodying my invention.

Fig. 2 is a side elevation partly in section of the device shown in Fig.1.

Fig. 3 is a sectional view taken along lines 3-3 of Fig. 1.

Referring more particularly to the drawing, reference numeral lindicates an insuf lating plate carrying a series of contacting bars 2.These bars each have a series of holes 3 therein which are adapted toreceive removable plugs 4. Positioned parallel with the face of the bankof bars 2 is a support of insulating' material 5 having secured to thebottom side thereof a hinge member 6 carrying a plurality of arms 8pivotally secured thereto at 7, one of said arms cooperating with eachof said bars. The free end of each arm has on the side adjacent the barsa cam-like projection 9 and at its rear side has secured a pin 10. Thispin passes through a hole 13 in an'angle iron or bar 11 which is securedto the insulating support 5. Encircling the pin 10 is a thin coil spring85 12 and for preventing the spring from passing through the hole 13 inthe angle iron a washer 14 is furnished. The hole 13 is made larger, asby elongation, than the pin 10 in order to permit freemovement of thelatter as the arm 8 is rocked slightly away from the bar 2 by Contactwith the plug 4. The arms 8 are held against the forward thrust ofspring 12 by a stop member 28 which is fastened to a projection at eachend of the 95 support 5. The arms rest against this stop member and arethereby'spaced the proper distance with respect to the bars 2 and plugs4. This arrangement gives a smoother' and a more uniformly resilientlight spring ac- 1&0

tion than can be obtained with a leaf spring or similar arrangement. Theangle iron 11 serves the additional function of electrically tyingtogether all of the contact arms 8 thereby insuring a multiplicity ofelectrical connections between each of the arms 8 and the member 6. Inoperation when one terminal 15 of circuit to be controlled is connectedto the member 6 the other terminal is connected to the various bars 2through control resistances which are not shown. While the hinge 7 of asingle contact arm 8 might be suiliciently conductive for ordinarypurposes much more reliable action is obtained by the mechanismdisclosed wherein the spring 12 conducts the operating current to themember 11 from whence it is in turn directed to the member 6 through allof the other springs and hinges of the arms in the bank.

The msulating support 5 is pivotally mounted at 16 on a stationarymember 17, so that the support and the contactor arms carried therebymay be swung out of engagement with the contact plugs of the bars. Forholding the support in its proper operating position a latch 18 is used,which engages with -a stationary member 19. This latch comprises a pinor bolt 2O slidably positioned in an aperture in a block 21 attached tothe support 5. This pin has therein a slot 22 through which passes alever 23 having an operating knob 24:. The lever 23 is pivotallyconnected to the block 21 at 25 so that when the knob 24 is moved in aright hand direction, as viewed in F ig. l, the pin 2O will be withdrawnfrom the hole 26 in a member 19 thereby permitting the support 5 to beswung away from the bank of bars. A spring 27 is furnished formaintaining the pin 20 in a forward position and edges of the slot 22are rounded to permit free movement of the lever 23 therein. This latcharrangement is very reliable and is easy to operate. The leverarrangement 23 permits the latch to be opened quickly and easily and yetdoes not interfere with the smooth action o the latch upon opening andclosing thereo In contacting banks of this type it is eX- tremelyimportant to have a reliable and quickly operable latching means. Itmust be quickly operable because adjustments of the bank have to be madefrom time to time rapidly, and it must be reliable because if the latchdoes not hold the support 5 as it is swung hurriedly to its closedposition, the various electric circuits will not be properly operated,with the result that if the contactipg mechanism is used in conjunctionwith a lm printing machine, a large amount of expensive film may bedestroyed.

I have disclosed a particular embodiment of my invention merely for thepurpose of illustration and it should be understood that variousmodifications may be made within the scope of the invention as set forthmthe following claim.

What I claim is:

Switching mechanism, comprisin the combination of a coordinate array ocontacts, the contacts n each row being electricall connected together,and a linear array o contacts relatively movable with respect to saidcoordinate array of contacts and extending thereacross, and means forsupporting said linear array of contacts, comprising a cross-bar ofinsulating material, each of the contacts supported thereby comprising apivoted contact member having an inclined contact face for slidingengagement with a linear array of said coordinate contacts, a stopmember mounted on said cross-bar and common to said pivoted contactsthereon for limiting the movement of said linear array of contactstoward said coordinate array of contacts, a tail member for each of saidpivoted contacts, a sprin on each of said tail members for urging saipivoted contacts toward said stop member,

and an apertured backbar attached to said crossbar, the apertures insaid backbar cooperating wi h said tail member for guiding purposes andfor electrically connecting said pivoted contacts, and an electricalterminal for one of said pivoted contacts.

In testimony whereof, I have signed my name to this specification this10th day of March, 1930.

ARTHUR ROSS.

